1. Field of the Invention
This invention relates generally to ice makers and, more particularly, to an improved ice maker for use in domestic refrigerators and the like including a fail-safe mode of operation.
2. Description of Background Art
In one form of an ice maker, an ice mold and associated mechanism are mounted in the freezer compartment of a domestic refrigerator/freezer apparatus. One example of such an ice maker is illustrated in Chesnut et al., U.S. Pat. No. 4,756,165, which is owned by the assignee of the present invention. Such an ice maker includes a mold in which water is frozen to form an ice body. Also included are an electric motor and an ejector blade for ejecting the ice body from the mold. An electric heater is in heat transfer association with the mold operable to free the ice bodies from the mold prior to the operation of the ejector blade to eject the ice bodies. A control circuit includes a thermostat responsive to the temperature of water in the mold. A thermostat switch is controlled by the thermostat to initiate operation of the motor for ejecting the ice body upon complete freezing thereof and concurrently energizing the heater. An electric circuit means includes the thermostat switch, the motor and a second switch controlled by the operation of the motor for maintaining energization of the motor independently of the first switch and causing the thermostat switch to control further energization of the heater whereby the thermostat switch de-energizes the heater within a single revolution of the ejecting means.
During normal operation of the ice maker described in the '165 patent, a bail arm is provided for sensing the amount of ice collected in a subjacent collection bin. The bail arm can be used as by raising the same to disable operation of the ice maker prior to a harvesting cycle. During a harvesting cycle, the bail arm is automatically raised in order to sense amount of ice in the bin. If insufficient ice is contained in the bin, then during the harvesting cycle the bail arm will be lowered to allow for completion of the harvest cycle and commencement of a subsequent ice making operation.
Occasionally, obstructions may exist in the freezer compartment which prevent the bail arm from lifting. In the ice maker described in the Chesnut et al. '165 patent the motor drives the ejector blade via a shaft having a cam. The cam operates a lever arm which is operable to lift the bail arm. In the presence of an obstruction, the motor will continue rotation possibly resulting in breakage of the lever arm. Alternatively, the lever arm used on the ice maker disclosed therein is designed to be flexible so that the torque produced by the motor causes bowing of the lever arm to bypass the cam so that the harvesting operation continues. Particularly, the lever arm includes a cam follower actuated by the cam which is designed to bypass the cam under an excessive torque condition. Consequently, upon completion of the harvesting cycle, a subsequent ice making operation will begin. Assuming that the obstruction is not removed, then an overproduction of ice can result because the bail arm is obstructed from sensing a full ice bin condition.
In the design of ice makers it is also desirable that ice being ejected from the mold be ejected into the collecting bin, rather than allowing the ice bodies to fall behind the mold. Also, it is desirable to minimize underproduction failures, such as ice bodies pinched between the ejector and stripper or bail arm and support housing.
The disclosed invention is intended to solve one or more of the problems discussed above in a novel and simple manner.